On Sun, Jul 1, 2012 at 6:45 PM, erik quanstrom <[email protected]>wrote:
> > Many compilers do just that, however, that said, unless the compiler is
> > prepared for it, since it effectively yields a struct of zero size which
> > normally is a no-go, it could produce bugs involving sizeof,
> initializers,
> > pointer addition et al, even some divisions by zero if the compiler is
> > making certain assumptions already, unless it already can have zero
> length
> > objects of this nature for some other reasons.
>
> actually, kenc is pretty good about all these. if you have
>
> struct fu {void x;};
>
> and take sizeof(struct fu), that will give a diagnostic error.
>
> the reason i avoided it was to not mess with the grammer, but if this is a
> common thing, maybe it's no big deal.
>
> though as charles points out, it is a bit of a waste of time.
>
If my memory serves, there is some wiggle room in C89 about how the empty
struct works, though generally it wouldn't fly, and C99 disallows it, while
C++ allows it (but it's sizeof > 0). Plus it's a common extension made
prevalent via gcc.
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